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THOMAS F. BAKER, OF ClNCINNATI, OHIO.

Letters Patent N 90,219, dated May 18, 1869.

The Schedule referred to in these Letters Patent and making part of the same,

To whomI it may conce/rn.'

Be it known that l, 'lnoAIAs F. Banen, ot' Cincinnati, Haniilton county, Ohio, have. invented anew and useful Iinprovenu-.nt in Jail-Doors and Grat-ings; and l hereby declare the following to he a tnli, clear, and exact description thereof, reference being had to the accompanying,r drawings, making.;l part otmy speeitii'ation.

This invention relates toa mode oi` construeting the hars ot'jaibgratings, which renders them impregnable to any attempts to saw the same asunder on the part of' prisoners or others.

Figure l is a perspective view of aportion of a jaildoor or grating, embodying my invention.

Figure 2 is al vertical sect-ion showing; two of the collars in position. y

Figure i is a horizontal seetion at the line X X.

A. are two longitudinal bars o1' stiles, and

B are cross-bars or rails rmly riveted to the tbrmer.

Both stiles and rails have stoel pieces, C, riveted,l

welded, or otherwise l'irmly attached to all their accessible surfaces.

Dare wrought-iron rods extending,r vertically through the rails from top to bottom, and firmly riveted at their ends.

Those portions ot' eaeh rod between the rails, are encircled b v steel sleeves, E, Whose ends pass into counter-bores, F, in the steel facing, so as to preclude the insertion of asaw or otherinstrument. Said sleeves saw.

These sleeves are in my preferred form enclosed in an external sleeve, G, of wrought lor east'iron, which may be either fixed or rotary, and are useful to prevent the inner sleeve beinr held against rot-ation under the action ot'a saw or tile.. But these external sleeves may, in someinstances, be omitted. Moreover, the rails and stiles may he made, wholly of steel.

[t will be observed that these steel sleeves are so short as to be easily brought to a hard temper without such curvature as would prevent the insertion of the rods.

l have selected, i'or illustration, the form success` fully intrmlneed by me, but may vary the same as cases or circumstances may suggest.

I claim herein as new, and of my invention- 1. The mode of constrnctinfbr a jail-door or grating with steel, or steel-faced stiles and ra-ils A B, rods D, and steel sleeves E, counter-sunk into the rails, as set forth.-

2. The combina-tion ofthe two concentric sleeves E and G, substantially as and for the purposes set forth.

In testimony' of which invention, I hereunto set my hand.

T. F. BAKER.

Witnesses:

GEO. H. KNIGHT, J .unas H. LAYMAN.

are capable of rotating:- easily under the action of a 

